Iran's judiciary has arrested some people for their role in the crash of a Ukrainian plane that Tehran said was accidentally hit by an Iranian missile, judiciary spokesman Gholamhossein Esmaili said on Tuesday.
He did not give further details.
President Hassan Rouhani today said in a televised speech that Iran will punish all those responsible for the accidental shooting down of the passenger plane.
He also said the "tragic event" would be investigated thoroughly.
"It was an unforgivable error ... one person cannot be solely responsible for the plane crash," he said.
"Iranian armed forces admitting their mistake is a good first step ... We should assure people that it will not happen again," he said, adding that his government was "accountable to Iranian and other nations who lost lives in the plane crash".